In order to guarantee water N resistance of watches worn on the wrist to a depth of immersion which may nominally reach thirty odd meters, mounting an acoustic transducer in the watch case without any communication path being provided between the transducer and the exterior capable of directly leading the sound waves is already known from the prior art. Such an assembly has the advantage of guaranteeing very good water tightness for the watch. However, since the acoustic energy has to reach the transducer or originate therefrom through the solid wall of the case, this solution is only possible if one is satisfied with mediocre acoustic quality. The band of frequencies which can be used is thus limited to the frequencies which succeed in passing through said wall. In practice, one has to work with the transducer resonance frequencies, these frequencies only being able to be transmitted effectively through a wall of the case if they correspond to a resonance frequency of such wall. This necessarily limits the range of frequencies able to be transmitted and is thus not suited to reproduction and/or reception of complex sounds such as speech or music. It will also be noted that such a wall inconveniently absorbs transmission of sounds transmitted or received by the transducer.